Cut my muffler in half 91 vfr750

Ok so i cut my muffler in half just behind behind the second chamber. Drilled the cap out and reinstalled the cap using pop rivets.
The sound, I absolutely love it.
Jetting. the carbs had 130 mains. I installed 132.5
everything off idle is perfect everything i could ask for.
while at an idle in traffic the engine gets up into the opperating temp and it gets sluggish, give it a little twist and it clears right up. But then goes back into its less than ideal state of idle.
I know as a motor gets warmer is gets richer witch me think at first it was going fat.
as the engine gets hot idle goes lower. I have not experieced any detonation. Just the shitty idle after it gets warm.
Could this be pilot jets?
I dont think it is a needle jet problem because i believe that the needle only effects 20/80 on the throttle.
any help would be appreciated

 

Try adjusting the idle mixture screews they control idle mixture, turning in clockwise is usually leaner.